EnumerableUnion should use array comparator when row type is ARRAY

0: jdbc:calcite:model=target/test-classes/mod> select count(*), max(deptno) from emps e1 union select count(*), max(deptno) from emps e2;
+---------------------+--------+
|       EXPR$0        | EXPR$1 |
+---------------------+--------+
| 5                   | 40     |
| 5                   | 40     |
+---------------------+--------+